Cross cylinder flip mechanism

ABSTRACT

In an ophthalmic refractor improved cross cylinder flip mechanism comprises a cross cylinder lens rotatably mounted in a loupe by means including a pinion meshed with a face gear, the latter being rotatable to achieve a flip, rotation of the face gear being actuated from a handgrip located adjacent the cylinder lens axis control knob, thereby minimizing the attention which a practitioner must give to frequent shifts of his hand from one such handgrip to the other.

United States- Patent Pitchford [54] CROSS CYLINDER FLIP MECHANISM [72] Inventor: Richard L. Pitchford, Brockport,

[73] Assignee: Bausch & Lomb Incorporated,

Rochester, N.Y.

221 Filed: July 22,1971 211 App]. Nay 165,218

[52] U.S.Cl ..351/28,35l/29 [51] Int.- Cl. ..A6lb 3/02, A 61b 3/08 [58] Field ofS ea'rch .....351/2 8,29

[56] References Cited UNITEDESTATES PATIENTS Wilkinsonnh; 351 29 1s] 3,698,799 4 1 Oct.17.,l972

Primary Examiner-David Schonberg Assistant Examiner-Paul A. Sacher Attorne y-Frank C. Parker et al.

57 ABSTRACT In an ophthalmic refractor improved cross cylinder flip mechanism comprises a cross cylinder lens rotatably mounted in a loupe by means including a -pinion meshed with a face gear, the latter being rotatableto achieve a flip, rotation of the face gear being actuated from a handgrip'located adjacent the cylinder lens axis control knob, thereby minimizing the attention which a practitioner must give to frequent shifts of his hand from one such handgrip to the other. I

I 11 Claims, 1 Drawing Figure PATENTED our 11 I972 RICHARD L. PITCHFORD INVENTOR.

1v wv JOHN E. LEONARZ ATTORNEY ing a cross cylinder flip mechanismin an ophthalmic refractor;

2.Description ofthe Prior Art A refractor is an instrument used in analyzing a pa-' tients visual defects and in determining suitable optical prescriptions for corrective eyewear. Such corrections annular or semicircular mount having opposing protru- Sims connected-by a diameter, which is the flip'axis,

one of the protrusions having a pinion mounted thereon. The other protrusion on the 'lensmount is cooperative with a detent which seats" at the two fully flipped positions of the'cross cylinder lens. The pinion is meshed with an annular face gearwhich is remotely rotatable from a control knob whichis coaxial with the may require greater or lesser powers of either or both spherical or cylindrical lenses. Accordingly, refractors commonly feature a plurality of different powered test lenses arranged in carriers, generally disc-shaped and rotatable, and the lenses thereby may be selectively-interposed over viewingholes aligned with a patients eyes until an optimum correction is achieved.

It is desirable that a carrier for cylinder test lenses should have the cylinder axis correctly aligned to the patients axis of astigmatism, and to this end means is commonly provided to cause each of the test cylinder lenses to arrive across the viewing tube with its axis at the same angular orientation as its-predecessor.

In performing a refraction involving cylinder lenses, it is often indicated to perform certain additional visual tests. particularly a cross cylinder test. Cross cylinder a'pparatus is commonly mounted on .the exterior of a cylinder lens axis control knob and shaft.

Accordingly, inoperation the practitioner will use the axis controlknob tojjselect an axis on'a'trial basis,

and thenper'form" the cross cylinder fliptest, interrogating the patient to determine the suitability of the corre'ctions being achieved with each flip. The analysis proceeds on a trial and'error basis with several alternations between the 'axis controlknob and the flip actua- -',tor knob until eventually an optimum-correction is refractor-to be pivoted across the axis of the viewing tube to complement the refraction of a test cylinder lens already present, 'an important test being performed by flipping a cross cylinder lens, incorporated in the cross cylinder apparatus, about' a: flip axis. A cross cylinder lens is regarded as having two axesThe first axis is parallel with its cylinder; thesecond is perpendicular to the first.'The flip axis is at 45 to both. The test is performed with the flip axis aligned with the cylinder axis of the test cylinder lens.

. Means for" automatically maintaining the synchronization of the cross cylinder flip axis with the cylinder'axis of the main cylinder lenses, is desirable in such instruments. Existing refractors provide a knob for rotating the lens carrier,-a'nd another kn'ob for rotating'the cylinder axis, how-ev.er, the-existing provision for actuating the flip mechanism consists of a small knurled wheel or handle attached directly to the cross cylinder lens mount. Motion studies which I have made indicate that a practitioner using a refractor spends a great amount of time moving hishand back and forth between the cylinder Iensaxis control knob and the flip-actuating handle, much of the time being taken up in orienting his hand to the location of the flip handle.

An improved flip-actuating mechanism, therefore,-

would be one located in a position more convenient to the normal resting place of the practitioners hand, i.e., the axis control knob. Additionally, such a mechanism should not require the practitioner to orient his hand in order to actuate the flip nor, for that matter, even to require the practitioners eye'to follow his hand movement. I am not aware'of any existing refractors featuring such flip-actuating mechanisms.

SUMMARY OF THE INVENTION mechanism I have mounted the cross cylinder lens in an determined. ,With my invention the practitioners hand is always immediately in position to actuate either knob without first having to search out the correctforientation. Since manypractitioners prefer to observe the pa- I tientsface as much as possible during the refraction it is important that the practitioners instrument leave his eyes as completely undistracted as possible.

In my invention Ialso employ a wheel detentably connected to the shaft which bears the cylinder lens axis control knob, the wheel being drivably connected to a loupe which mounts. the crosscylinderlens, this mechanism serving tosynchronize the angular rotations of the flip axis with those of the'cylind'er lens-axis. AXIS.

Since'it is further desirable to be able to rotate the cross cylinder lens through an angle of 45 about the axis of the viewing tube, and to. make such rotation without disturbing the orientation of the main cylinder lens, further provision is required to permit the loupe to be so rotated. My invention further comprises means by which the loupe maybegrasped by the practitioner for the purpose of accomplishing such, a rotation. Since theaxis of. the cylinder lens-in the viewing tube must remainjstill during this rotation I have provided the aforementioned detentable connection between the flip axis synchronizing sys'temand the cylinderlens axis control system. Since the latter has by far the greater friction the detent will slip when a rotational movement is imparted to the loupe,leaving the main cylinder axis undisturbed.

DESCRIPTION OF THE PREFERRED EMBODIMENT The drawing is a diagrammatic cross section of the cylinderlens control system and the cross cylinder Only a fragment of the instruments housing and chassis 12 appears, however it may be observed that a post 14 rises fromthe chassis to serve as a mount for various'apparatus'to be explained. Within the post 14 is journaled a cylinder axis control shaft 16 upon which is mounted a wheel 18 having a wire 20 pinned thereto. The wire 20 is tensioned by the idler 22 and is drivably connected to a mechanism for synchronizing the cylinder axes of a plurality of test cylinder lenses 24. Such mechanism, having been well known in the art for many years, and forming no part of the instantinvention, is not shown or described in detail herein. The test patients other eye. ln'refracting a. patient, then, the practitioner will rotate the shaft 16 and the attendant wheel 18 to vary the axes of the lenses 24 until the patient confirms that the axes aresubstantially correct. The carrier disc 26 is then rotated until a suitably powered lens is interposed before the viewing tube 28, as the patient will furtherconfirm by virtue of the improvement in his vision attributable thereto.

To facilitate the performance of cross cylinder tests, I. have provided cross cylinder apparatus in a housing 30, which is pivotally mounted on the post 14. A rotatable loupe 32 is provided within thehousing 30, positioned' to come into'coaxial alignment withthe viewing tube 28 when the housing 30 is rotated about the post of meshed gears. f:

l Thus it may be seen thatairotational movement applied by the practitioners hand to the actuator knob 58 is transmitted via the tube 56, wheel 54 and belt 52 to the face. gear 50, which, engaged withthe pinion 46, rotates the pinion and itsattendant lens mount 42 and cross cylinder lens 36. The cam '44 and detent 48 serve to enforce complete 180 rotations of the lens 36-. It shouldbeobservedthat the flip actuator knob 58 is immediately proximate and adjacent to the cylinder lens :axis control knob 60 which is rigidly connected to the shaft l6 and thence controls the axis selection mechanism previouslydescribed. As the practitioners hand moves from an axis adjustment-to a flip movement and back again, as is anextremely common movement during a typical refraction, the knobs S8 and 60,,serve as location references for each other due to their proximity and the practitioner never has to divert his eyes from more important phenomenae in order to achieve such transfers of his hand.

Maximum convenience and reliability in the-use of a r'efractor requires that the practitioner not be required 14. An adjustable detent 34 is present to assure ready alignment of the loupe 32 with the viewing tube 28, when so rotated. A weak cross cylinder lens 36 is shown rotated 90 between its normal positions so as to present a plan view in the drawing. It may be observed that, as shown in the plan'view, the lens cylinder axes 38 and 39 form an angle of 45f with the flip axis 40. The cylinder lens itself ismounted in a rotatable mount 42 'having' protrusions 44 and 46 thereon: which are coaxial withthe flip axis 40.'T he protrusion 44 takes the form of a'cam which is cooperative withthe springbiased detent 48 to afford the practitioner a feel for the fully flipped positions of the cylinder lens 36. As shown, the detent 48 is fully compressed and would not reach its extended position against the cam 44 until the lens 36 and mount 42 were rotated another 90.

Meanwhile the other protrusion takes the form of a pinion 46. Both'protrusions 44 and 46 are formed with round shank portions which are suitably journaled in .bearing ports formed in the loupe 32 thereby defining a convenient axis 40 forflip rotation of the lens. 36 and mount 42. The pinion 46 is in mesh with a face gear 50 which is freely rotatable relative to the loupe 32. By a face gear I mean simply a substantially annular member having teeth along at leastone face of the annulus which are cooperative with the teeth of the pinion 46 to induce the pinion's rotation.

to realign the cross cylinder flip axis 40. to the test' cylinder lens axis eachtime a cross cylinder test is to be performed, and therefore mechanism is provided to synchronize the two axes. Connected to the knob 60 is detent 62 which provides a yieldable clutch connection to the toothed wheel 64. The teeth onthewheel 64 are engaged with teeth on a belt 66 which additionally enfga'ge teeth formed onthe lower periphery of the loupe The loupe 32 provides little resistance to move-.

ments transmitted via thedetent 62 from the cylinder lens axis control knob 60. The force of the turning loupe 32 is transmitted through the detent 48 to the lens mount 42, pinion 46, face gear 50, belt 52, wheel 54, tube 56 and'knob 58 which latter, being without a load, turns freely. The detent 62 may therefore be seen .to require means, well known in the art, to provide a sufficiently strong bias, and resistance to slipping, to overcome inertias and residual frictions in the members intervening between it and theknob 58. By careful choice of the transmission ratio provided between the wheel 64 and the loupe 32 to correspond with that between the wheel 18 and its attendant cylinder lenses 24, synchronization is maintained between the flip axis and the test lens axis.

The face gear 50 is furnished with teeth along its rim as well as its face and is therefore rotatable in response to movements of the toothed belt 52 with which it is engaged and which is further engaged with a toothed wheel 54. The latter is coupled by means of a hollow transmission tube 56 to a'tlip actuator knob 58. The toothed belt may be of the kind known as a timing belt. Other direct drive means may be employed to make a driving connection between the wheel 54 and the face gear 50. For example, the belt 52 may be a beaded chain or other chain cooperative with suitable configw rations on the face gear-50 and wheel Additionally, the driving connection might take the form of a wire suitably secured to the face gear and wheel, or it might undisturbed while the cross cylinder lens is rotated.

As and when it occasionally becomes necessary to loupe 32 by the practitioners grasp on a handgrip, such as the exterior knurling 68, on the loupe 32. Such an impulse is simultaneously transmitted through the loupe 32, directly to the belt 66, and indirectly, by the detent 48, mount42, pinion 46 and face gear 50, to the belt 52. Since the'belt S2'is loaded only by the wheel 54 and the unencumberedjflip actuator knob 58, these members rotate idly in response to-- the impulse. The more direct portion of the practitioners impulse acts through the belt 66 on the .wheel 64 and is brought to bear against the detent 62-; Since the detent 62 is loaded by the knob 60, the shaft 16 and its attendant test cylinder lens axis adjustment mechanism, the detent 62 yields, leaving the test cylinder lens axis Since in individual instruments the friction inherent in the test cylinder lens axis adjustment mechanism may be inadequate to insure the yielding of the detent 62, a friction disc 70 is provided at the base of the shaft 16 by means of which a suitable amount of friction may be incorporated into the structure.

I claim:

1. In vision analysis apparatus includingi a viewing tube;

means for interchanging a plurality of cylinder lenses across said viewing tube, means responsive to a control knob for aligning the cylinder axes ofsaid lenses to a predetermined angle across said viewing tube; and cross cylinder means including a cross cylinder lens, a mounting loupe, and means responsive to said control knob for synchronizing the flip axis of said cross cylinder means with said predetermined angle of said cylinder lens axis, improved flipping means for said cross cylinder means including flip actuating means proximate to said cylinder lens axis control knob, comprising: a. a lens mount for said cross cylinder lens having a protrusion journals d in a wall ofsaid loupe; b. a pinion affixed to said lens mount; g 1 c. a face gear mounted rotatably' relative to said loupe and in meshing contact with said pinion; and d. actuating means proximate said cylinder lens axis control knob and drivably connected to said face gear for rotating said. face gear while in mesh with said pinion. 2. The improvement of claim 1 wherein said actuating means comprises a power train, including:

a shaft coaxial with said axis control knob; a handgrip member affixed to said shaft and proximate said knob; a first wheel affixed to said shaft; and

direct drive means connecting said first wheel with I 5. The improvement of claim 2 wherein saiddirect drive means comprises wire means connected to said first wheel and further connected to said face gear.

6. The improvement of claim 2, wher ein said direct drive means comprises a gear train connected to said first wheel and further connected to said face gear.

7. The improvement of claim 1 wherein said lens mount is connected tosaidloupe by first detent means defining positions of said cross cylinder lens transverse to said viewing tube.

8! The improvement of claim' 2 wherein said lens mount is connected to said loupe by first detent means responsive to positions of said cross cylinder lens transverse to said viewing tube.

9. The improvement of claim8 wherein said loupe is connected to a second wheel coaxial with said cylinder lens axis control knob b direct drive means, 'd second wheel being ,deten t ably connected by seci iid detent means to said knob for transmitting axis changing movements of said knob synchronously to both said cylinder lenses and to said cross cylindermeans.

10. The improvement of claim 9 wherein said loupe further comprises handgripmeans adapted for receiving a rotational manipulation transmissable to said loupe, said direct drive means and said second wheel;

said second detent means including means .yieldable to such rotational manipulation so transmitted to break and detentable connection of said second detent means, for rotation of said loupe independently of said cylinder lens axis 'control knobs rotation.

11. In vision analysis apparatus including:

a viewing tube;

means for interchanging a plurality of cylinder lenses across said viewing tube;

means responsive to a control knob for aligning the cylinder axes of said lenses to a predetermined angle across said viewing tube; and

cross cylinder means including a cross cylinder lens,

a mounting loupe, and means responsive to said control knob for synchronizing the flip axis of said cross cylinder means with said predetermined angle of said-cylinder lens axis, improved flipping means for said cross cylinder means, comprising:

a. a lens mount for said cross cylinder lens said mount including'means journaled in a wall of said loupe;

b. a pinion coaxial with said flip axis and drivably connected to said lens mount;

c. means for rotating said pinion; and

d. actuating means for said pinion rotating means, said actuating means being disposed adjacent said cylinder lens axis control knob. 

1. In vision analysis apparatus including: a viewing tube; means for interchanging a plurality of cylinder lenses across said viewing tube; means responsive to a control knob for aligning the cylinder axes of said lenses to a predetermined angle across said viewing tube; and cross cylinder means including a cross cylinder lens, a mounting loupe, and means responsive to said control knob for synchronizing the flip axis of said cross cylinder means with said predetermined angle of said cylinder lens axis, improved flipping means for said cross cylinder means including flip actuating means proximate to said cylinder lens axis control knob, comprising: a. a lens mount for said cross cylinder lens having a protrusion journaled in a wall of said loupe; b. a pinion affixed to said lens mount; c. a face gear mounted rotatably relative to said loupe and in meshing contact with said pinion; and d. actuating means proximate said cylinder lens axis control knob and drivably connected to said face gear for rotating said face gear while in mesh with said pinion.
 2. The improvement of claim 1 wherein said actuating means comprises a power train, inclUding: a shaft coaxial with said axis control knob; a handgrip member affixed to said shaft and proximate said knob; a first wheel affixed to said shaft; and direct drive means connecting said first wheel with said face gear for flipping said cross cylinder lens.
 3. The improvement of claim 2 wherein said direct drive means comprises a chain engaged with protrusions on said first wheel and further engaged with protrusions on said face gear.
 4. The improvement of claim 2 wherein said direct drive means comprises a timing belt engaged with protrusions on said first wheel and further engaged with protrusions on said face gear.
 5. The improvement of claim 2 wherein said direct drive means comprises wire means connected to said first wheel and further connected to said face gear.
 6. The improvement of claim 2, wherein said direct drive means comprises a gear train connected to said first wheel and further connected to said face gear.
 7. The improvement of claim 1, wherein said lens mount is connected to said loupe by first detent means defining positions of said cross cylinder lens transverse to said viewing tube.
 8. The improvement of claim 2 wherein said lens mount is connected to said loupe by first detent means responsive to positions of said cross cylinder lens transverse to said viewing tube.
 9. The improvement of claim 8 wherein said loupe is connected to a second wheel coaxial with said cylinder lens axis control knob by direct drive means, said second wheel being detentably connected by second detent means to said knob for transmitting axis changing movements of said knob synchronously to both said cylinder lenses and to said cross cylinder means.
 10. The improvement of claim 9 wherein said loupe further comprises handgrip means adapted for receiving a rotational manipulation transmissable to said loupe, said direct drive means and said second wheel; said second detent means including means yieldable to such rotational manipulation so transmitted to break said detentable connection of said second detent means, for rotation of said loupe independently of said cylinder lens axis control knob''s rotation.
 11. In vision analysis apparatus including: a viewing tube; means for interchanging a plurality of cylinder lenses across said viewing tube; means responsive to a control knob for aligning the cylinder axes of said lenses to a predetermined angle across said viewing tube; and cross cylinder means including a cross cylinder lens, a mounting loupe, and means responsive to said control knob for synchronizing the flip axis of said cross cylinder means with said predetermined angle of said cylinder lens axis, improved flipping means for said cross cylinder means, comprising: a. a lens mount for said cross cylinder lens said mount including means journaled in a wall of said loupe; b. a pinion coaxial with said flip axis and drivably connected to said lens mount; c. means for rotating said pinion; and d. actuating means for said pinion rotating means, said actuating means being disposed adjacent said cylinder lens axis control knob. 